Today, in the United States, railway grain cars are in short supply, and elevator managers all over the Midwest are suffering from an inability to move their grain to terminal elevator facilities. The severe shortage of grain storage space makes attractive use of open top hopper cars, which normally are employed in hauling coal, and which commonly are available. This alternative service of coal cars, of course, necessitates use of a cover for protecting the grain from water damage and wind loss, and the prior art contains various proposals for removable cover systems. Although some of these proposals are available commercially, none of them, in my opinion, is entirely satisfactory.
The object of this invention is to provide an improved removable cover system for converting an open top hopper car into an acceptable grain-hauling car. This new cover system is characterized by various important features, the more notable of which are:
1. It is made of easily fabricated metal components joined, as far as practicable, by welding. Thus the system is economical and is more durable and more reliable than the tarpaulin type covers which some have proposed.
2. The system consists of sections, each of which spans the width of the hopper car, which are bolted together end-to-end to span the car's length. The arrangement makes it a simple matter to accommodate the wide variety of car sizes presently used by the U.S. railroads. It also enables the cover to be installed and removed relatively easily by a small crew equipped with common tools and aided by a trackside crane of reasonable capacity.
3. The sections of the cover are secured to the car by J-bolts which engage the outturned flanges at the upper margins of the side and end walls of the car. Therefore, the system complies with the regulations of the Association of American Railroads (known as the AAR), which prohibit drilling or welding of the car body. Moreover, the attachment scheme precludes undue displacement of the cover under normal service conditions, yet accomodates the small relative displacements attributable to deflection and twisting of the car during transit. The scheme also permits, with only minor damage, the substantial displacements of the cover which can occur as a result of large impact loads, such as those which may be encountered in a derailment.
4. The sections carry depending, exterior skirts which project downward below the upper margins of the car walls, and which, in the aggregate, envelope the perimeter of the car. This feature minimizes entry of rain, sleet, or snow. In addition, these skirts enclose from the outside the J-bolts, and thereby protect those components from damaging impacts with obstruction which are encountered along a right-of-way, particularly on sidings.
5. The roof sections preferably also are provided with interior depending skirts which serve as dams which minimize escape of grain during filling of the car and also when the car is in transit.
6. The cover sections employ an arched design which increases the hauling capacity of the cars and makes them comparable to covered grain cars.
7. All sections are provided with walkways, and all except very short sections are equipped with hatchways having hinged covers. Therefore, cars covered with these sections may be filled and handled just as easily as standard grain cars. The preferred hatchways are unusually easy to construct, yet they afford adequate insurance against entry of water and escape of grain.